1. Field of the Invention
The present invention relates to a thin film magnetic head comprising at least one of an inductive type thin film magnetic head for writing and a magnetoresistive type thin film magnetic head for reading, and also relates to a method of manufacturing such a thin film magnetic head. Particularly, the present invention relates to a combination type thin film magnetic head comprising an inductive type thin film magnetic head for writing and a magnetoresistive type thin film magnetic head for reading which are supported by a substrate in a stacked manner.
2. Description of the Related Art
Recently a surface recording density of a hard disc device has been improved, and it has been required to develop a thin film magnetic head having an improved performance accordingly. There has been proposed and actually used a combination type thin film magnetic head including an inductive type thin film magnetic head for writing and a magnetoresistive type magnetic head for reading, said magnetic heads being supported by a substrate in a stacked fashion. As the reading magnetic head utilizing the magnetoresistive effect, there has been generally used a reading magnetic head utilizing an anisotropic magnetoresistive (AMR) effect, but there has been also developed a magnetic head utilizing a giant magnetoresistive (GMR) effect having a resistance change ratio higher than the normal anisotropic magnetoresistive effect by several times. In the present specification, these AMR and GMR elements are termed as a magnetoresistive type thin film magnetic head or simply MR reproducing element.
By using the AMR element, a very high surface recording density of several gigabits per a unit square inch has been realized, and a surface recording density can be further increased by using the GMR element. By increasing a surface recording density in this manner, it is possible to realize a hard disc device which has a very large storage capacity of more than 10 gigabytes and is still small in size.
A height (MR Height) of a magnetoresistive reproducing element is one of factors which determine a performance of a reproducing head including a magnetoresistive reproducing element. This MR height is a distance measured from an air bearing surface on which one edge of the magnetoresistive reproducing element is exposed to the other edge of the element remote from the air bearing surface. During a manufacturing process of the magnetic head, a desired MR height is obtained by controlling an amount of polishing the air bearing surface.
At the same time, a performance of a recording head has been also required to be improved in accordance with the improvement of the reproducing head. In order to increase a surface recording density, it is necessary to make a track density on a magnetic record medium as high as possible. For this purpose, a width of a pole portion at the air bearing surface has to be reduced to a value within a range from several micron meters to several sub-micron meters. In order to satisfy such a requirement, the semiconductor manufacturing process has been adopted for manufacturing the thin film magnetic head.
One of factors determining a performance of an inductive type thin film magnetic film for writing is a throat height (TH). This throat height is a distance of a pole portion measured from the air bearing surface to an edge of an insulating layer which serves to separate electrically a thin film coil from the air bearing surface. It has been required to shorten this distance as small as possible. Also this throat height is determined by an amount of polishing the air bearing surface.
In order to improve the performance of the combination type thin film magnetic head including a stack of an inductive type thin film magnetic head for writing and a magnetoresistive type thin film magnetic head for reading, it is important that the inductive type thin film magnetic head for writing and magnetoresistive type thin film magnetic head for reading are formed with a good balance.
FIGS. 1-6 show successive steps of manufacturing a known typical thin film magnetic head, in which A represents a cross sectional view cut along a plane perpendicular to the air bearing surface and B denotes a cross sectional view cut along a plane parallel with the air bearing surface. FIG. 7 is a plan view illustrating a whole structure of the known thin film magnetic head. This magnetic head belongs to a combination type thin film magnetic head which is constructed by stacking an inductive type thin film writing magnetic head and a magnetoresistive type thin film reading magnetic head one on the other.
At first, as illustrated in FIG. 1, on a substrate 1 made of, for instance aluminum-titan-carbon (AlTiC), is deposited an insulating layer 2 made of alumina (Al2O3) and having a thickness of about 5-10 xcexcm. A first magnetic layer 3 serving as a magnetic shield for protecting the MR element of the reading head from an external magnetic field is formed with a thickness of 3 xcexcm Then, after depositing by sputtering an insulating layer 4 serving as a shield gap layer made of an alumina with a thickness of 100-150 nm as shown in FIG. 2, a magnetoresistive layer 5 having a thickness not larger than 10 nm and being made of a material having the magnetoresistive effect, and the magnetoresistive layer is shaped into a desired pattern by a highly precise mask alignment. Next, an insulating layer 6 serving as a second shield gap layer is formed to embed the magnetoresistive layer 5 within the shield gap layer consisting of the insulating layers 4 and 6.
Next, as shown in FIG. 3, a second magnetic layer 7 made of a permalloy and having a thickness of 3 xcexcm is formed. This second magnetic layer 7 serves not only as the other shield layer for magnetically shielding the MR reproducing element together with the above mentioned first magnetic layer 3, but also as one of poles of the inductive type writing thin film magnetic head to be manufactured later.
Next, after forming, on the second magnetic layer 7, a write gap layer 8 made of a nonmagnetic material such as alumina to have a thickness of about 200 nm, a magnetic layer made of a magnetic material having a high saturation magnetic flux density such as permalloy (Ni 50 wt %: Fe 50 wt %) and iron nitride (FeN), and this magnetic layer is shaped into a given pattern by a highly precise mask alignment to form a pole chip 9. A width W of the pole chip 9 defines a track width. Therefore, in order to attain the high surface recording density, it is necessary to narrow the width W of the pole chip 9 as small as possible. During the formation of the pole chip 9, a dummy pattern 9xe2x80x2 for connecting the second magnetic layer 7 with a third magnetic layer constituting the other pole is formed. This dummy pattern makes the formation of a through hole easy after mechanical polishing or chemical-mechanical polishing (CMP).
Then, in order to prevent an increase of an effective track width, that is, in order to prevent a spread of a magnetic flux at the lower pole during a writing operation, the gap layer 8 and second magnetic layer 7 constituting the other pole are removed by an ion beam etching such as an ion milling, while the pole chip 9 is utilized as a mask. The thus formed structure is called a trim structure, and the trim structure constitutes a pole portion of the second magnetic layer.
Furthermore, as depicted in FIG. 4, after forming a depression in a surface of the second insulating layer 7, an insulating layer 10 made of an alumina is formed to have a thickness of about 3 xcexcm. Then, a first layer thin film coil 11 made of, for instance a copper is formed on the insulating layer 10 as shown in FIG. 5, and assembly is flattened by CMP. Then, after forming an electrically insulating photoresist layer 12, a surface of the photoresist layer is flattened by baking at a temperature of, for instance 250-300xc2x0 C.
Next, on the flat surface of the photoresist layer 12, a second layer thin film coil 13 is formed. This second layer thin film coil 13 is connected to the first layer thin film coil 11 and these first and second layer thin film coils constituting a thin film coil. However, a connecting portion of these thin film coils is not shown in the drawing. Then, after forming a photoresist layer 14 on the second layer thin film coil 13 with a highly precise mask alignment, the photoresist layer is baked at 250xc2x0 C. to be reflowed. A reason for forming the photoresist layers 12 and 14 with a highly precise mask alignment is that the throat height and MR height are determined with respect to edges of these photoresist layers on a side of the pole portion.
Next, a third magnetic layer 15 made of, for instance a permalloy is formed selectively on the pole chip 9 and photoresist layers 12 and 14 such that the third magnetic layer has a thickness of 3 xcexcm and is shaped into a desired pattern. The third magnetic layer 15 is brought into contact with the first magnetic layer 7 at a position remote from the pole portion by means of the dummy pattern 9xe2x80x2, and therefore the thin film coil 11, 13 pass through a closed magnetic path constituted by the second magnetic layer, pole chip and third magnetic layer.
Furthermore, after depositing an overcoat layer 16 made of an alumina on an exposed surface of the third magnetic layer 15 as illustrated in FIG. 6, a wafer is cut into bars and a side wall of a bar at which the magnetoresistive layer 5 and gap layer 8 are formed is polished to form an air bearing surface (ABS) 17. During the formation of the air bearing surface 17, the magnetoresistive layer 5 is also polished to obtain an MR reproducing element 18. In this manner, the above mentioned throat height TH and MR height MRH are determined by the polishing. This condition is shown in FIG. 10. In an actual manufacturing process, contact pads for establishing electrical connections to the thin film coils 11, 13 and MR reproducing element 18 are formed, but these contact pads will be explained later.
As shown in FIG. 6, an angle xcex8 (Apex angle) between a straight line S connecting side edges of the photoresist layers 12, 14 isolating the thin film coils 11, 13 and an upper surface of the third magnetic layer 15 is one of important factors for determining a property of the thin film magnetic head together with the throat height TH and MR height MRH.
Furthermore, as shown in the plan view of FIG. 7, the width W of the pole chip 9 and pole portion 19 of the third magnetic layer 15 determines a width of tracks recorded on a record medium, and therefore it is necessary to make this width W as small as possible in order to realize a high surface recording density. It should be noted that in the drawing, the thin film coils 11, 13 are denoted to be concentric for the sake of simplicity.
The above mentioned combination type thin film magnetic head is practically used in a hard disk device, in which in order to prevent the head from being worn by contact with a surface of a record medium, it is necessary to separate the head from the record medium during the operation. At the same time, in order to increase the record density, it is required to bring the head and record medium close to each other as far as possible. In the known thin film magnetic head, in order to solve the above mentioned contradict problems, the surface of the head opposing to the record medium is formed as the air bearing surface 17 and a very thin air layer of several tens nano meters is produced therebetween by the rotation of the record medium. For producing the stable air layer, projections are generally formed in the air bearing surface 17 in accordance with a given pattern.
FIG. 8 is a plan view showing the air bearing surface 17. In this figure, a dimension A is equal to a thickness of the AlTiC substrate 1. An arrow B denotes a rotating direction of the record medium. In the air bearing surface 17, there is formed a projections 20 for generating a stable air layer. For the sake of clarity, portions of the air bearing surface except for the projections, i.e. depressed portions are denoted by hatching. A whole assembly in which the thin film magnetic head is installed and the projections 20 are formed in the air bearing surface 17 is generally called a slider.
FIG. 9 shows a side surface of the slider on which the thin film magnetic head is installed. In the combination type thin film magnetic head, the inductive type thin film magnetic head for writing and magnetoresistive type thin film magnetic head for reading are provided in a stacked fashion, and there are provided two contact pads 21 and 22 (W1 and W2) for connecting the thin film coils 11, 13 of the inductive type thin film magnetic head to a recording circuit and two contact pads 23 and 24 (R1 and R2) for connected either ends of the magnetoresistive element 18 of the magnetoresistive type thin film magnetic head to a reading circuit.
When the slider having the above mentioned combination type thin film magnetic head is installed in a hard disk device, the slider 28 is fixed, with an adhesive, to a flexure portion 27 formed at a front end of a suspension 26 which is formed by a resilient strip such as stainless steel foil. At a front end of the flexure portion 27, there are formed four interconnecting contact pads 31-34 to which the contact pads 22-25 formed on the slider 28 are connected by means of contact tips called apple bond.
As illustrated in FIG. 10, the interconnecting contact pads 31-34 provided on the flexure portion 27 of the suspension 26 are connected, via wiring patterns 35-38, to external contact pads 41-44, respectively in a vicinity of a mount plate 39 of the suspension 26, said external contact pads being connected to the externally provided writing circuit and reading circuit. In order to avoid undesired crossings of the wiring patterns 35-38, the interconnecting contact pads 31-34 have different aligning order than the external contact pads 40-43.
The above explained combination type thin film magnetic head is manufactured by various processes including photomask process, plating process, sputtering process, etching process, ion milling process and flattening process such as CMP. Combination type thin film magnetic heads having various performances and properties can be obtained by changing a track width and a thickness of the magnetoresistive element 18 of the magnetoresistive type thin film magnetic head as well as a track width of the inductive type thin film magnetic head defined by a width of pole portion 19. On the other hand, in accordance with the diversification of hard disk devices, combination type thin film magnetic heads having various properties have been required. In order to obtain such customer orientated combination type thin film magnetic heads, the magnetoresistive layer 5 and pole tip 9 are formed to be coincided with a required track width and the air bearing surface 17 is polished to attain required throat height TH and MR height MR. In this manner, customer oriented combination type thin film magnetic heads having performances and properties required by customers are prepared by changing various parameters in the manufacturing processes. Therefore, it takes a rather long time to make a delivery of customer oriented thin film magnetic heads.
Furthermore, customers have required not only a variety of the above mentioned performances and properties which are determined by the manufacturing processes, but also a variety of sliders 28 flying above record surfaces of hard disks. For instance, FIG. 9 shows a center element type slider in which the thin film magnetic head is provided at a center of the slider viewed from the traveling direction of the record medium, and FIG. 11 illustrates a side element type slider, in which a thin film magnetic head is provided near a side of the slider.
It should be noted that the center element type slider having the thin film magnetic head provided at a center and the side element type slider having the thin film magnetic head situating near a side of the slider could not be manufactured by the same process. Therefore, a customer orientated slider having desired type, performance and property could not be delivered within a short time.
A record capacity of a hard disk device has been increased, and two, three or four hard disks are used in a stacked fashion and magnetic heads are provided on either surfaces of a hard disk. Therefore, there are provided an up-type slider which is arranged above a hard disk and a down-type slider which is arranged below a hard disk. The slider shown in FIG. 9 is a center element type slider of up-type, and the slider illustrated in FIG. 11 is a side element type slider of up-type. These up-type sliders are arranged above a hard disk. In the above explanation, hard disk is arranged horizontally, but in actual hard disk devices, hard disks are arranged vertically. In this case, sliders are arranged on right and left sides of the hard disk. However, in the present specification, these sliders are also called up-type slider and down-type slider for the sake of explanation.
In order to shorten a time for delivery, one may consider common use of a same slider. However, when the up-type slider is used as the down-type slider, a position of a magnetic head might be deviated (for instance, if the head is positioned right side in the up-type, the head becomes left side in the down-type). Therefore, in general, a single side element type slider could not be commonly used as the up-type slider and down-type slider. Although the center type slider does not have such a problem, a positional relationship of contact pads becomes problem.
In the up-type slider shown in FIG. 9, the left hand two contact pads 21 and 22 are connected to either ends of the thin film coils 11, 13 of the inductive type writing thin film magnetic head, and right hand two contact pads 23 and 24 are connected to either ends of the magnetoresistive element 18 of the magnetoresistive type reading thin film magnetic head. These contact pads are connected to the interconnecting contact pads 31-34, respectively provided on the flexure portion 27 the suspension 26. When this slider is used as the down-type slider, the two contact pads 21 and 22 connected to the thin film coils 11, 13 become right hand contact pads and the two contact pads 23 and 24 connected to the magnetoresistive element 18 become left hand contact pads.
It should be noted that the position of the external contact pads 41-44 provided on the suspension 26 supporting the slider is not changed when the slider is used as the up-type or down-type slider. Therefore, when the slider is used as the up-type one, the contact pads 23 and 24 connected to the magnetoresistive element 18 are connected to the interconnecting contact pads 31 and 32, respectively which are connected to the externally connecting contact pads 41 and 42, respectively, and at the same time, the contact pads 21 and 22 connected to the thin film coils 11, 13 are connected to the interconnecting contact pads 33 and 34, respectively which are connected to the externally connecting contact pads 43 and 44, respectively. That is to say, the magnetoresistive element 18 is connected to the external contact pads 41 and 42 situating near the mount plate 39 and the thin film coils 11, 13 are connected to the external contact pads 43 and 44 remote from the mount plate.
When the slider is used as the down-type one, the contact pads 21 and 22 connected to the thin film coils 11, 13 are connected to the interconnecting contact pads 34 and 33, respectively which are connected to the externally connecting contact pads 41 and 42, respectively, and at the same time, the contact pads 23 and 24 connected to the magnetoresistive element 18 are connected to the interconnecting contact pads 32 and 31, respectively which are connected to the externally connecting contact pads 43 and 44, respectively. In this manner, in contradict to the above mentioned up-type slider use, the thin film coils 11, 13 are connected to the external contact pads 43 and 44 situating near the mount plate 39 and the magnetoresistive element 18 is connected to the external contact pads 41 and 42 remote from the mount plate.
As explained above, when the known center element type slider is used as both the up-type and down-type, the positional relationship of the magnetoresistive element 18 and thin film coils 11, 13 connected to the externally connecting contact pads 41-44 provided in the vicinity of the mount plate 39 of the suspension 26 supporting the slider becomes reversed. Therefore, in the up-type use, the two inner contact pads 41 and 42 near the mount plate 39 have to be connected to the writing circuit and the two outer contact pads 43 and 44 have to be connected to the reading circuit, whilst in the down-type use, the two inner contact pads 41 and 42 near the mount plate 39 have to be connected to the reading circuit and the two outer contact pads 43 and 44 have to be connected to the writing circuit.
Upon assembling the hard disk device, it is quite inconvenient to change the connection of the writing circuit and reading circuit to the externally connecting contact pads 41-44 of the suspension 26 in accordance with the up-type and down-type. Therefore, manufactures of hard disk devices require slider which can be used both as the up-type and down-type without changing the connection of the externally connecting contact pads to the writing and reading circuits. Therefore, in known combination type thin film magnetic head, up-type sliders have different structure than down-type sliders. This is one of reasons of the long term delivery of sliders.
In the inductive type thin film magnetic head, a direction of a current passing through the thin film coils 11, 13 is sometimes defined by customers or head types. That is to say, some customers require heads in which the current flows from inside to outside, and other customers require heads in which the current flows from outside to inside. In such a case, a slider of either up-type and down-type could not be used commonly as long as the connection between the externally connecting contact pads and the writing circuit is not changed.
Moreover, in order to improve the record density, it has been proposed to utilize the GMR element instead of the usual AMR element. In the AMR element, it is not necessary to consider the polarity upon connecting it to the reading circuit. However, in the GMR element, the polarity of the connection to the reading circuit is specified. Therefore, the up-type slider including the GMR element could not be utilized as the down-type slider.
As explained above, in the known thin film magnetic head, particularly in the known combination type thin film magnetic head, various sliders having different structures must be manufactured in accordance not only with the center element type and side element type, but also with the up-type and down-type. In general, the manufacture of a single type thin film magnetic head requires 20-30 masks, the number of necessary masks becomes large in accordance with the variety of the slider types and the manufacturing cost becomes high.
In an actual manufacturing site, the customer""s request is predicted to a certain extent, and several types of sliders have been stocked. However, when specifications of customers are changed, the stocked slider could not be used, and new type sliders have to be manufactured. Therefore, a delivery of the new type slider could not be performed promptly, and it is very difficult to satisfy the delivery term of customers. If a manufacturing line is crashed by an insertion of speediest rots in regardless of mean cycle time, an important balance of the manufacturing line might be lost and a capacity of large scale production might be reduced.
Furthermore, if the prediction differs greatly from an actual order of customers, an amount of stocked sliders becomes large. Model change of hard disk devices has been effected more and more, and if the sliders are stocked for a long term such as several months, they might be bad backlog. This also results in the increase in the manufacturing cost.
In Japanese Patent Application Laid-open Publication Kokai Hei 11-149622, there is proposed a thin film magnetic head, in which upon forming an element of a combination type thin film magnetic head of side element type, a plurality of auxiliary lead out lines are formed, and these auxiliary lead out lines are connected to a plurality of connection terminals connected to thin film coils and MR element by means of a plurality of element lead out lines in accordance with specifications of a magnetic head. In this known technique, a plurality of auxiliary lead out lines are fixed connected to the contact pads or connecting members connected to the contact pads in regardless of specifications of the head, and this connecting relationship could not be changed.
In the above mentioned prior art, a step of forming the element lead out lines for connecting the auxiliary lead out lines and the connection terminals to each other is an independent step or a same step in which contact pads or connecting members connected thereto are formed. The element lead out lines could not be manufactured in a same step of forming a structural element of the thin film magnetic head and could not be made of same materials as structural elements. Therefore, a number of photomasks used in the lithography is increased.
Furthermore, the above mentioned prior art publication does not teach that information denoting types of sliders is recorded on thin film magnetic heads. Therefore, customers could not easily confirm whether or not the delivered thin film magnetic heads belong to ordered ones. Moreover, when the delivered thin film magnetic heads are installed in hard disk devices, there might occur confusion.
In the above prior art, although it is possible to manufacture selectively side element type sliders of up-type and down-type, center element type sliders of up-type and down-type could not be manufactured. Further, the prior art does teach that up-type and down-type sliders of side element type or center element type are selectively manufactured.
The present invention has for its object to provide a thin film magnetic head, particularly a combination type thin film magnetic head, in which any required connection can be effected between a thin film magnetic head element and contact pads in accordance with desired specifications, and therefore almost all structures can be commonly used for various types of sliders and a delivery term can be shortened and cost can be decreased.
It is another object of the invention to provide a combination type thin film magnetic head, particularly a combination type thin film magnetic head, in which any required connection can be effected between a thin film magnetic head element and contact pads in accordance with desired specifications, and therefore almost all structures can be commonly used not only for up-type and down-type, but also for center element type and side element type and a delivery term can be further shortened and cost can be further decreased.
It is another object of the invention to provide a thin film magnetic head, in which connecting conductors for selectively connecting thin film coils and/or MR element to contact pads in accordance with required type can be made of a same material in a same step as structural components of thin film magnetic head element, and therefore the number of necessary photomasks can be reduced.
It is still another object of the invention to provide a thin film magnetic head, in which a type of the thin film magnetic head can be easily confirmed.
The present invention also relates to a method of manufacturing a thin film magnetic head, and has for its object to provide a method of manufacturing the above mentioned thin film magnetic head in an effective manner with a smaller number of photomasks at low cost.
According to the invention, a thin film magnetic head comprises:
a substrate constituting a slider having an air bearing surface which is to be opposed to a surface of a record medium;
at least one thin film magnetic head element supported by said substrate;
at least two contact pads for connecting first and second connection terminals of said at least one thin film magnetic head element to an external circuit, said at least two contact pads being provided on one end surface of the substrate viewed in a direction in which the record medium travels; and
a wiring pattern arranged to connect said first and second connection terminals of the thin film magnetic head element to said at least two contact pads in accordance with a desired positional relationship define by specifications of the thin film magnetic head.
In the thin film magnetic head according to the invention, said wiring pattern preferably comprises first and second conductive patterns including a plurality of connecting conductors which extend in different levels viewed from the substrate with interposing therebetween an insulating layer and are connected in an electrically conductive manner to said at least two connection terminals of said thin film magnetic head element as well as to said at least two contact pads directly or via another conductive pattern, and coupling conductors connecting said connecting conductors in different levels through contact holes formed in said insulating layer at plural cross points which are selected from a plurality of cross points of the connecting conductors of said first and second conductive patters in accordance with the specifications of the thin film magnetic head. Upon realizing the thin film magnetic head according to the invention, it is preferable that said wiring pattern is made of the same material as a conductive member constituting the thin film magnetic head element and is formed simultaneously with said conductive member.
In the thin film magnetic head according to the invention, said thin film magnetic head element is formed by an inductive type thin film magnetic head element and the first conductive pattern of said wiring pattern situating closer to the substrate is made of a same material as a lower magnetic pole of the inductive type thin film magnetic head element and is formed simultaneously with the lower magnetic pole and the second conductive pattern remote from the substrate is made of a same material as coil windings of a thin film coil and is formed simultaneously with the thin film coil; the first conductive patter closer to the substrate is made of a same material in a same process as the lower magnetic pole and the second conductive pattern remote from the substrate is made of a same material in a same process as an upper magnetic pole; the first conductive pattern closer to the substrate is made of a same material in a same process as lower coil windings of a thin film coil and the second conductive pattern is made of a same material in a same process as upper coil windings of the thin film coil; or the first conductive patter closer to the substrate is made of a same material in a same process as coil windings of a thin film coil and the second conductive pattern is made of a same material in a same process as an upper magnetic pole. In this manner, the first and second conductive patterns of the wiring pattern may be formed simultaneously with components of thin film magnetic head element, and therefore it is no more necessary to prepare a special photomask for manufacturing the wiring pattern and the number of total photomasks can be reduced.
In an embodiment of the thin film magnetic head according to the invention including at least the inductive type thin film magnetic head element, it is preferable that said contact holes for connecting the connecting conductors of the first conductive pattern with the connecting conductors of the second conductive pattern are formed in said insulating layer in a same process as a process in which an opening is formed in said insulating layer for forming a back gap at a position remote from a magnetic gap, said lower and upper magnetic poles being magnetically coupled with each other at said back gap. Also in this case, the number of photomasks may be reduced.
According to the invention, it is preferable to record information representing the specifications of the thin film magnetic head at a position which can be monitored from external. In this case, it is advantageous to form said information during a manufacturing process for electrically connecting a plurality of connecting conductors on different levels at a plurality of cross points selected in accordance with the specifications of the thin film magnetic head. In this case, information corresponding to the information formed on the thin film magnetic head may be formed on a photomask determining the specifications of the thin film magnetic head, and therefore the specifications of the thin film magnetic head can be always corresponded to the information formed on the thin film magnetic head, and any mistake can be removed. Moreover, the information of the thin film magnetic head may be recorded in such a manner that the information may be automatically read out by a reader or may be directly monitored by human beings.
The thin film magnetic head according to the invention includes several principal structural types. In a first principal structure, said connecting conductors of the first conductive pattern of the wiring pattern are fixedly connected to first and second connection terminals of said at least one thin film magnetic head, and said connecting conductors of the second conductive pattern are fixedly connected to said at least two contact pads. Here it should be noted that the term xe2x80x9cfixedly connectedxe2x80x9d means not only a direct connection, but also a connection by means of an intermediate conductor. The term xe2x80x9cfixedly connectedxe2x80x9d is used to express that the connecting conductors are not selectively connected in accordance with the specifications of the thin film magnetic head.
In this first principal structure, said connecting conductors of the first conductive pattern of the wiring pattern are directly connected to said first and second connection terminals of said at least one thin film magnetic head element, and said connecting conductors of the second conductive pattern are directly connected to said at least two contact pads; or said connecting conductors of one of the first and second conductive patters of the wiring pattern are directly connected to said first and second connection terminals of said at least one thin film magnetic head element, and said connecting conductors of the other conductive pattern are connected to another connecting conductors which extend in a different level than the first and second conductive patterns with interposing another insulating layer therebetween and are directly connected to said at least two contact pads through contact holes formed in said another insulating layer.
In a second principal structure of the thin film magnetic head according to the invention, said thin film magnetic head element is formed by a combination type thin film magnetic head element including an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, and there are formed two connection terminals connected to both ends of a thin film coil of the inductive type thin film magnetic head element, two connection terminals connected to both end of a magnetoresistive element of the magnetoresistive type thin film magnetic head element, and four contact pads. Said first conductive pattern of the wiring pattern includes four connecting conductors which are fixedly connected to said four connection terminals of the thin film magnetic head element, and said second conductive patter of the wiring pattern includes two connecting conductors which are fixedly connected to two contact pads among said four contact pads and two intermediate conductors having extended portions which cross two connecting conductors electrically connected to the remaining two contact pads.
In a third principal structure of the thin film magnetic head according to the invention, said thin film magnetic head element is formed by a combination type thin film magnetic head element including an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, and there are formed two connection terminals connected to both ends of a thin film coil of the inductive type thin film magnetic head element, two connection terminals connected to both end of a magnetoresistive element of the magnetoresistive type thin film magnetic head element, and four contact pads. Said first conductive pattern of the wiring pattern includes two connecting conductors which are fixedly connected to two connection terminals among said four connection terminals of the thin film magnetic head element and two intermediate conductors having extended portions which cross two connecting conductors electrically connected to the remaining two connection terminals, and said second conductive patter of the wiring pattern includes four connecting conductors which are fixedly connected to said four contact pads.
In a fourth principal structure of the thin film magnetic head according to the invention, said first conductive pattern of the wiring pattern includes four connecting conductors which are connected to first and second connection terminals of the thin film magnetic head element and said at least two contact pads, and said second conductive pattern includes intermediate conductors whose number is identical with that of the contact pads and which cross all connecting conductors of the first conductive pattern.
In the fourth principal structure of the thin film magnetic head according to the invention, said thin film magnetic head element is formed by a combination type thin film magnetic head element including an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, and both ends of a thin film coil of the inductive type thin film magnetic head element and both end of a magnetoresistive element of the magnetoresistive type thin film magnetic head element are connected to four connection terminals. These four connection terminals are connected to four contact pads by means of the wiring pattern which includes the first conductive pattern having four connecting conductors and the second conductive pattern having four intermediate conductors. Then, the thin film magnetic head may be commonly used as the center element type sliders of up-type and down-type, in which said combination type thin film magnetic head element is situated at a center of the air bearing surface viewed from a direction perpendicular to the end surface of the substrate on which said contact pads are formed.
Moreover in the fourth principal structure of the thin film magnetic head according to the invention, there are provided two combination type thin film magnetic head elements each of which includes an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, both ends of thin film coils of the two inductive type thin film magnetic head elements are connected to four connection terminals and both ends of magnetoresistive elements of the two magnetoresistive type thin film magnetic head elements are connected to four connection terminals, and these eight connection terminals are connected to four contact pads by means of the wiring pattern including the first conductive pattern having twelve connecting conductors and the second conductive pattern having four intermediate conductors. Then, the thin film magnetic head may be commonly used as the side element type sliders of up-type and down-type, in which the two thin film magnetic head elements are situated at positions which are symmetrical with respect to a center of the air bearing surface viewed from a direction perpendicular to the end surface of the substrate on which the contact pads are provided.
In the fourth principal structure of the thin film magnetic head according to the invention, there are provided three combination type thin film magnetic head elements each of which includes an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, both ends of thin film coils of the three inductive type thin film magnetic head elements are connected to six connection terminals and both ends of magnetoresistive elements of the three magnetoresistive type thin film magnetic head elements are connected to six connection terminals. These twelve connection terminals are connected to four contact pads by means of the wiring pattern including the first conductive pattern having sixteen connecting conductors and the second conductive pattern having four intermediate conductors. Then, the thin film magnetic head may be commonly used as the side element type sliders of up-type and down-type as well as the center element type sliders of up-type and down-type, in which one thin film magnetic head element is situated at a center of the air bearing surface and the remaining two thin film magnetic head elements are situated at side positions which are symmetrical with respect to the center of the air bearing surface viewed from a direction perpendicular to the end surface of the substrate on which the contact pads are provided.
The present invention also relates to an intermediate unit for thin film magnetic head which may be commonly used for thin film magnetic heads having different specifications, and has for its object to provide an intermediate unit for thin film magnetic head, by means of which a final thin film magnetic head can be promptly obtained by adding few manufacturing processes in accordance with desired specifications.
According to the invention, an intermediate unit of thin film magnetic head which can be commonly used for thin film magnetic heads having different specifications comprises:
a substrate constituting a slider having an air bearing surface which is to be opposed to a surface of a record medium;
at least one thin film magnetic head element supported by said substrate; and
a wiring pattern arranged such that a plurality of connection terminals of the thin film magnetic head element to a plurality of contact pads in accordance with a desired positional relationship defined by specifications of the thin film magnetic head, said contact pads being provided on an end surface of the substrate viewed in a traveling direction of the record medium for connecting said plurality of connection terminals of said at least one thin film magnetic head element to an external circuit.
In a preferable embodiment of the intermediate unit for thin film magnetic head according to the invention, said wiring pattern comprises first and second conductive patterns including a plurality of connecting conductors which extend in different levels viewed from the substrate with interposing therebetween an insulating layer and are connected in an electrically conductive manner to at least two connection terminals of said thin film magnetic head element as well as to at least two contact pads directly or via another conductive pattern. In this case, it is preferable to form said wiring pattern by a same manufacturing process with a same material as a conductive member constituting the thin film magnetic head element.
In a first principal structure of the intermediate unit for thin film magnetic head according to the invention, the connecting conductors of the first conductive pattern of the wiring pattern are fixedly connected to first and second connection terminals of said at least one thin film magnetic head element, and the connecting conductors of the second conductive pattern are fixedly connected to said at least two contact pads.
In a second principal structure of the intermediate unit for thin film magnetic head according to the invention, said thin film magnetic head element is formed by a combination type thin film magnetic head element including an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, and there are formed two connection terminals connected to both ends of a thin film coil of the inductive type thin film magnetic head element, two connection terminals connected to both end of a magnetoresistive element of the magnetoresistive type thin film magnetic head element, and four contact pads. Said first conductive pattern of the wiring pattern includes four connecting conductors which are fixedly connected to said four connection terminals of the thin film magnetic head element, and said second conductive patter includes two connecting conductors which are fixedly connected to two contact pads among said four contact pads and two intermediate conductors having extended portions which cross two connecting conductors electrically connected to the remaining two contact pads.
In a third principal structure of the intermediate unit for thin film magnetic head according to the invention, said thin film magnetic head element is formed by a combination type thin film magnetic head element including an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, and there are formed two connection terminals connected to both ends of a thin film coil of the inductive type thin film magnetic head element, two connection terminals connected to both end of a magnetoresistive element of the magnetoresistive type thin film magnetic head element, and four contact pads. Said first conductive pattern of the wiring pattern includes two connecting conductors which are fixedly connected to two connection terminals among said four connection terminals of the thin film magnetic head element and two intermediate conductors having extended portions which cross two connecting conductors electrically connected to the remaining two connection terminals, and said second conductive patter of the wiring pattern includes four connecting conductors which are fixedly connected to said four contact pads.
In a fourth principal structure of the intermediate unit for thin film magnetic head according to the invention, said thin film magnetic head element is formed by a combination type thin film magnetic head element including an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, and both ends of a thin film coil of the inductive type thin film magnetic head element and both end of a magnetoresistive element of the magnetoresistive type thin film magnetic head element are connected to four connection terminals, and the wiring pattern is formed such that said four connection terminals may be connected to four contact pads by means of the wiring pattern which includes the first conductive pattern having four connecting conductors and the second conductive pattern having four intermediate conductors. Then, the combination type thin film magnetic head element may be commonly used as the center element type sliders of up-type and down-type, in which said combination type thin film magnetic head element is situated at a center of the air bearing surface viewed from a direction perpendicular to the end surface of the substrate on which said contact pads are formed.
In a fifth principal structure of the intermediate unit for thin film magnetic head according to the invention, there are provided two combination type thin film magnetic head elements each of which includes an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, both ends of thin film coils of the two inductive type thin film magnetic head elements are connected to four connection terminals and both ends of magnetoresistive elements of the two magnetoresistive type thin film magnetic head elements are connected to four connection terminals, and said wiring pattern is formed such that said eight connection terminals may be connected to the four contact pads by means of the wiring pattern including the first conductive pattern having twelve connecting conductors and the second conductive pattern having four intermediate conductors. Then, said two combination type the thin film magnetic head elements may be commonly used as the side element type sliders of up-type and down-type, in which the two thin film magnetic head elements are situated at positions which are symmetrical with respect to a center of the air bearing surface viewed from a direction perpendicular to the end surface of the substrate on which the contact pads are provided.
In a sixth principal structure of the intermediate unit for thin film magnetic head according to the invention, there are provided three combination type thin film magnetic head elements each of which includes an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element formed to be supported by the substrate in a stacked fashion, both ends of thin film coils of the three inductive type thin film magnetic head elements are connected to six connection terminals and both ends of magnetoresistive elements of the three magnetoresistive type thin film magnetic head elements are connected to six connection terminals, and the wiring pattern is formed such that said twelve connection terminals may be connected to four contact pads by means of the wiring pattern including the first conductive pattern having sixteen connecting conductors and the second conductive pattern having four intermediate conductors. Then, said three combination type thin film magnetic head elements may be commonly used as the side element type sliders of up-type and down-type as well as the center element type sliders of up-type and down-type, in which one thin film magnetic head element is situated at a center of the air bearing surface and the remaining two thin film magnetic head elements are situated at side positions which are symmetrical with respect to the center of the air bearing surface viewed from a direction perpendicular to the end surface of the substrate on which the contact pads are provided.
Furthermore, the present invention relates to a method of manufacturing a thin film magnetic head including a substrate constituting a slider having an air bearing surface which is to be opposed to a surface of a record medium, at least one thin film magnetic head element supported by said substrate, at least two contact pads for connecting first and second connection terminals of said at least one thin film magnetic head element to an external circuit, said at least two contact pads being provided on one end surface of the substrate viewed in a direction in which the record medium travels, and a wiring pattern arranged to connect said first and second connection terminals of the thin film magnetic head element and said at least two contact pads through first and second conductive patterns. According to the invention, a method of manufacturing such a thin film magnetic head comprises:
a step of forming said thin film magnetic head element such that the thin film magnetic head element is supported by the substrate;
a step of forming a plurality of connecting conductors and/or intermediate conductors constituting the first conductive pattern of the wiring pattern;
a step of forming an insulating layer such that said first conductive pattern of the wiring pattern is covered with the insulating layer;
a step of forming, on said insulating layer, the second conductive pattern of the wiring pattern, said second conductive pattern including a plurality of connecting conductors and/or intermediate conductors each of which crosses respective one of said plurality of connecting conductors and/or intermediate conductors of the first conductive pattern of the wiring pattern;
a step of electrically connecting said connecting conductors and/or intermediate conductors of the first and second conductive patterns through contact holes formed in said insulating layer at a plurality of cross points selected in accordance with specifications of the thin film magnetic head to be manufactured among all cross points of the connecting conductors and/or intermediate conductors of the first and second conductive patters;
a step of forming an overcoat layer at least on said end surface of the substrate; and
a step of forming said at least two contact pads on said overcoat layer such that said contact pads are connected to said at least two connection terminals.
In the method of manufacturing the thin film magnetic head according to the invention, said first and second conductive patterns of the wiring pattern is preferably made of a same material in a same manufacturing process as an electrically conductive member of the thin film magnetic head element, and furthermore conductive members connecting these first and second conductive patterns are preferably made of a same material in a same process as the conductive member of the thin film magnetic head element.
In a case of forming a part or all of the wiring pattern is formed by a same material in a same process as the conductive member of the thin film magnetic head element, the first conductive pattern may be formed by a same material in a same process as a lower magnetic pole of an inductive type thin film magnetic head element and the second conductive pattern may be made of a same material as coil windings of a thin film coil and is formed simultaneously with the thin film coil; the first conductive patter may be made of a same material in a same process as the lower magnetic pole and the second conductive pattern may be made of a same material in a same process as an upper magnetic pole of the inductive type thin film magnetic head element; the first conductive pattern may be made of a same material in a same process as upper coil windings of a thin film coil and the second conductive pattern may be made of a same material in a same process as upper coil windings of the thin film coil; or the first conductive patter may be made of a same material in a same process as coil windings of a thin film coil and the second conductive pattern may be made of a same material in a same process as an upper magnetic pole.
In the method of manufacturing the thin film magnetic head according to the invention, it is preferable that said contact holes for connecting the first conductive pattern with the second conductive pattern are formed in said insulating layer in a same process as a process in which an opening is formed in said insulating layer for forming a back gap at a position remote from a magnetic gap, said lower and upper magnetic poles being magnetically coupled with each other at said back gap.
In the method of manufacturing the thin film magnetic head according to the invention, it is preferable to record information representing the specifications of the thin film magnetic head at a position which can be monitored from external. It is advantageous to form such information during a manufacturing process for electrically connecting a plurality of connecting conductors on different levels at a plurality of cross points selected in accordance with the specifications of the thin film magnetic head. In this case, information corresponding to the information formed on the thin film magnetic head may be formed on a photomask determining the specifications of the thin film magnetic head, and thus the specifications of the thin film magnetic head can be always corresponded to the information formed on the thin film magnetic head, and any mistake can be removed. Moreover, the information of the thin film magnetic head may be recorded in such a manner that the information may be automatically read out by a reader or may be directly monitored by human beings.
The present invention also relates to a method of manufacturing a thin film magnetic head by utilizing the above mentioned intermediate unit for thin film magnetic head, and according to the invention a method of manufacturing a thin film magnetic head comprises:
a step of preparing and stocking a number of intermediate units for thin film magnetic head, each including a substrate constituting a slider having an air bearing surface which is to be opposed to a surface of a record medium, at least one thin film magnetic head element supported by said substrate, and a wiring pattern arranged such that a plurality of connection terminals of the thin film magnetic head element to a plurality of contact pads in accordance with a desired positional relationship defined by specifications of the thin film magnetic head, said contact pads being provided on an end surface of the substrate viewed in a traveling direction of the record medium for connecting said plurality of connection terminals of said at least one thin film magnetic head element to an external circuit; and
a step of electrically connecting said first and second conductive patterns at a plurality of cross points selected in accordance with specifications of the thin film magnetic head among cross points between said first and second conductive patterns of the wiring pattern.
In such a method of manufacturing the thin film magnetic head according to the invention, information representing the specifications of the thin film magnetic head is preferably formed during said step of electrically connecting said first and second conductive patterns at a plurality of cross points selected in accordance with specifications of the thin film magnetic head among cross points between said first and second conductive patterns of the wiring pattern.
In the method of manufacturing the thin film magnetic head according to the invention, said step of electrically connecting the first and second conductive patterns of the wiring pattern may be carried out in various ways. For instance, the first and second conductive patterns may be connected by means of coupling conductors at a plurality of contact holes determined in accordance with the specifications among contact holes formed in the insulating layer at all cross points between the first and second conductive patterns.
Alternatively, coupling plugs are formed in all contact holes formed in the insulating layer such that the contact holes extend from an upper surface of the first conductive pattern to an upper surface of the second conductive pattern, and a plurality of coupling plugs and the second conductive pattern are electrically connected to each other by means of coupling patches at a plurality of cross points determined in accordance with the specifications of the thin film magnetic head. Furthermore, a plurality of contact holes are formed in the insulating layer at a plurality of cross points determined in accordance with the specifications of the thin film magnetic head such that said contact holes extend up to the first conductive pattern, and the second conductive pattern is connected to the first conductive pattern by means of said contact holes.
As stated above, in case of forming the contact holes at the cross points, after forming the necessary connection, the contact holes may be covered with an insulating layer, and a plurality of contact pads may be formed on this insulating layer such that the contact pads are connected to the second conductive pattern or conductive members connected thereto. In this case, the contact pads may be formed to have a large area extending above the wiring pattern, and therefore even if an end surface of a small slider becomes small, the contact pads having a large surface area can be obtained.